Diseases and Conditions
What is atrial fibrillation?
Normally, the heart pumps in a well-timed fashion. The two upper chambers (atria) contract first followed by the two lower chambers (ventricles). This coordinated pumping is powered by the heart's own electrical system and efficiently pumps blood out to the body and back. In atrial fibrillation (AF), a type of arrhythmia, the electrical signals fire rapidly and chaotically. This causes the atria to quiver instead of contracting normally. Many of the signals also reach the ventricles, causing them to contract irregularly too. This results in a fast and irregular heart rhythm. Over time, this can weaken the heart and lead to heart failure. Plus, when the atria do not contract effectively, the blood may pool in the heart. This increases the risk that a blood clot may form and travel to the brain causing a stroke. People with AF are 5 to 7 times more likely to have a stroke than people who do not have AF.
AF is more common in people who are over 65 and is seen more often in men than women.
What are the symptoms of atrial fibrillation?
You may not have symptoms with AF. But, when ventricles are not able to pump enough blood out to the lungs and body, it can cause these symptoms:
Heart palpitations or fluttering in the chest
Shortness of breath
Dizziness and faintness
Some people with AF have intermittent episodes (intermittent or paroxysmal AF). Others have chronic or persistent AF.
What causes atrial fibrillation?
AF can develop when someone who has underlying heart disease, such as heart valve disease, heart attack, or heart failure. High blood pressure, thyroid problems, excess alcohol use, sleep apnea, and certain lung diseases can also cause AF.
How is atrial fibrillation treated?
Some people with atrial fibrillation will return to normal rhythm without treatment. They will "convert" on their own back to normal rhythm. Treatment decisions depend in part on whether symptoms are bothersome and how long your heart has been in AF. For most people, treatment of AF involves attempts to restore (reset) the heart back to its normal rhythm (rhythm control) or to control the heart rate (rate control). Sometimes surgery or a procedure called catheter ablation is used. In addition, a person with AF is given medications to prevent blood clots to reduce the risk of stroke.
Rhythm control. Rhythm control is an attempt to reset the heart back to its normal rhythm. It can be done with medications or electrical shock.
Anti-arrhythmic medications, such as sodium channel blockers or potassium channel blockers, slow the heart's ability to send electrical signals.
Electrical cardioversion involves sending an electrical shock through paddles placed on the chest. Usually doctors will want you to take blood thinners for a period of time before electrical cardioversion to reduce the risk of a stroke from a dislodged blood clot.
Rate control. Medications to help control the heart rate include
Beta blockers, such as atenolol or metoprolol. These drugs slow the heart rate.
Calcium channel blockers, such as diltiazem or verapamil. These drugs slow the heart rate.
Digoxin. This drug slows the electrical currents between the upper and lower chambers.
Catheter ablation. In this procedure, a catheter is guided through a blood vessel to the heart. Here energy is sent through the catheter to destroy small areas of heart tissue responsible for the arrhythmia. It may be an option when medications are not working.
Maze procedure. This is a surgical procedure in which areas of the heart are cut to create a "maze" of scar tissue that prevents the erratic electrical signals from passing through the heart.
Treatment to prevent blood clots. People with AF will be prescribed blood thinners to reduce the risk for stroke. This may include aspirin, clopidogrel, warfarin, dabigatran, or rivaroxaban. Your doctor will have a detailed discussion with you about which blood-thinning medications are most appropriate for you.